eplace `-v` Operator to Ensure Compatibility (#1185)

Replaced the `-v` operator with a more universally compatible method for variable checking in the bash script. The update uses parameter expansion to check if a variable is set, ensuring the script runs smoothly on environments with different Bash versions.

Issue: https://github.com/openimsdk/open-im-server/issues/1182

scripts/lib/color.sh

@@ -20,7 +20,7 @@
 ################################################################################
 
 # shellcheck disable=SC2034
-if [[ ! -v COLOR_OPEN ]]; then
+if [ -z "${COLOR_OPEN+x}" ]; then
     COLOR_OPEN=1
 fi